WASHINGTON (CNN) — Top intelligence officials indicated on Tuesday that the GOP was also a Russian hacking target but that none of the information obtained was leaked.
FBI director James Comey told a Senate panel that there was "penetration on the Republican side of the aisle and old Republican National Committee domains" no longer in use.
He later added that "there was evidence of hacking directed at state-level organizations, state-level campaigns, and the RNC, but old domains of the RNC, meaning old emails they weren't using. None of that was released."
Comey said there was no sign "that the Trump campaign or the current RNC was successfully hacked."
Asked by Sen. Mark Warner, a Virginia Democrat on the Senate intelligence committee, whether the hacker had the ability to selectively leak that old information, Comey indicated that they did.
Director of National Intelligence James Clapper told the Senate committee, examining the cyber breaches, that the intelligence community concluded with "high confidence" that Russia hacked the election to "denigrate" Democratic presidential candidate Hillary Clinton and contrast her unfavorably to Republican Donald Trump.
"We have multiple high quality sources that contribute to that assessment," Clapper said. "Attributing cyber operations is difficult but not impossible."
Tuesday's hearing is the first public examination of Russia's activities since President-elect Trump received a briefing from the country's top intelligence officials on Moscow's interference in the presidential election.
The 17 US intelligence agencies already issued a statement in October expressing their unanimous assessment that Moscow had probed state election voting centers and penetrated the email accounts of Democratic groups and individuals. Much of that information was made public through the organization WikiLeaks, lead by Julian Assange.
In classified and declassified reports released last week, they outlined their findings that Russian President Vladimir Putin not directly ordered the "influence campaign."
Republicans and Democrats both called for a thorough investigation into Russia's hacking of the presidential election Tuesday, reaffirming their confidence in US intelligence agencies' findings even as President-elect Donald Trump has continued to downplay them.
The report "gives me no reason to doubt the findings," said the chairman of the Senate intelligence committee, North Carolina Republican Richard Burr. "We owe it to the American people to do an independent and bipartisan review."
Congressional Democrats are pushing for a bipartisan, independent commission to look into the hacks. California Democratic Sen. Dianne Feinstein said last week that she and other senators will soon introduce a similar bill, while House lawmakers introduced one in early December and re-introduced it again last week.
Republicans have preferred to limit investigations to congressional committees they control. On Tuesday, the ranking Democrat on the House intelligence committee, California's Adam Schiff, said "the seriousness of these allegations warrant the most thorough and non-partisan of investigations."
Another California Democrat on the committee, Eric Swalwell, said the "best way forward is to have an independent, bipartisan commission that can depoliticize this. The Democrats were the victims this time," but "it could be the Republicans next time. The constant should be that both parties care about our democracy. There's plenty of room for Republicans to come on board."
In the final run-up to Nov. 9, Russia shifted its focus from influencing the campaign to undermining the validity of the results, a theme that Trump himself began to stress on the campaign trail, telling people the election was going to be "rigged."
During the campaign, Trump cited information released by WikiLeaks more than 100 times, CNN's Jake Tapper has found.
Prior to his briefing on that report, Trump had rejected the intelligence community's findings, accusing them of being politically partisan and, by raising faulty intelligence gathered during the Iraq War, implying that they were not competent.
After the officials' briefing of around 90 minutes, Trump issued a statement that downplayed Russia's role, lumping it in with "China, other countries, outside groups and people" who are "consistently trying to break through the cyber infrastructure of our government institutions."
Some of the intel leaders and Senate lawmakers had aired their concern in a hearing last week that Trump's apparent support for figures like Assange and his dismissal of the intelligence findings have undermined morale within intelligence agencies and pose broader dangers. If US intelligence agencies don't have the trust and confidence of the president, analysts say other countries' intelligence services will have less of an incentive to work closely with them.